Challenges

When you think about air pollution’s effect on your health, it’s probably your lungs you’re most worried about.
But studies show that exposure to the tiniest air pollutant particles — particles 30 times smaller than the width of a human hair, often carried in smoke or exhaust fumes — is linked to decreased brain volume and the risk of a faster decline in thinking and memory skills with age.
One such study, published in November 2020 in the journal Neurology, looked at women in their 70s and 80s who lived in high air pollution areas. The researchers, who took brain scans of the women at the beginning and end of the five-year study, found that breathing in these kinds of airborne particles was linked to shrinkage in the areas of the brain vulnerable to Alzheimer’s disease — the equivalent of a 24 percent increased risk of the disease over five years.
But another study suggests that at least one or two servings of fish weekly may counteract some of air pollution’s effects on the brain, according to research first published in July 2020 in the journal Neurology.
Researchers found that among older women in the United States who lived in areas with high levels of air pollution, those who had the highest blood levels of omega-3 fatty acids had significantly less brain shrinkage than women with the lowest levels. These healthy unsaturated acids are in fish, like salmon and tuna, and other seafood, as well as in nuts, seeds and plant oils.
Women with the highest omega-3 blood levels also had greater brain volume in the hippocampus, the region of the brain associated with memory.
“Our project is just one of many studies supporting that healthy lifestyle, including healthy diet, is a good strategy to slow down age-related cognitive decline,” study coauthor Ka Kahe, a professor of epidemiology and obstetrics and gynecology at Columbia University’s Irving Medical Center, told AARP in an email.
The findings suggest that “higher levels of omega-3 fatty acids in the blood from fish consumption may preserve brain volume as women age and possibly protect against the potential toxic effects of air pollution,” Kahe wrote in a press release.
One reason may be that omega-3 fatty acids have been shown to fight inflammation in aging brains and to reduce brain damage caused by neurotoxins like lead and mercury, Kahe explained.
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